A coupler cylinder is driven between a locked state and an unlocked state of a bucket by being supplied with hydraulic oil. A main pump supplies the hydraulic oil to the coupler cylinder. A pressure increasing valve controls the supply of the hydraulic oil to the coupler cylinder. A controller controls drive of the pressure increasing valve. The controller instructs the pressure increasing valve to stop the supply of the hydraulic oil to the coupler cylinder based on pressure in an oil passage between the main pump and the coupler cylinder.

A pilot hydraulic system may include a pilot pressure source, a pilot pressure return tank, a pilot valve, a pilot pressure supply line connecting the pilot pressure source to the pilot valve, and a pilot pressure return line connecting the pilot pressure return tank to the pilot valve. A main control valve may include a pilot chamber. A pilot pressure control line connects the pilot valve to the pilot chamber. A hydraulic sub-system is provided for modifying pilot pressure provided to the pilot chamber of the main control valve. The hydraulic sub-system may include a variable orifice valve disposed in the pilot pressure control line, a pilot pressure bypass line communicating the pilot pressure control line downstream of the variable orifice valve with the pilot pressure return line, and an electrohydraulic pressure reducing valve (EHPRV) disposed in the pilot pressure bypass line.

A work vehicle includes computing system is configured to receive a first and seconds inputs associated with controlling an operation of first and second hydraulic loads. Furthermore, the computing system is configured to control the operation of the first or second flow control valve corresponding to the one of the first or second hydraulic loads associated with the greater hydraulic fluid pressure based on the corresponding received first or second input. Additionally, the computing system is configured to determine the first or second pressure of the hydraulic fluid being supplied to another of the first or second hydraulic loads. Moreover, the computing system is configured to control the first or second flow control valve corresponding to the other of the first or second hydraulic loads based on the corresponding received first or second input and the determined first or second pressure.

To achieve improvement in work efficiency of calibration work and improvement in calibration accuracy, by performing control so that the time taken to increase the sweep of an applied current becomes substantially constant, upon the calibration of a valve opening position current value when a valve operated by electrical current applied to an electrical actuator opens a flow passage. There is provided a predicted value calculating means for predicting a calibration value of a valve opening position current value on the basis of information concerning valve opening position current values, and the sweep starting current value is set so that the time taken to increase the sweep to a predicted value predicted by the predicted value calculating means from a sweep start becomes a fixed time.

An example valve includes: (i) a valve body comprising a supply port and an operating port; (ii) a sleeve comprising a first opening fluidly coupled to the supply port, a second opening fluidly coupled to the operating port, and a seat; (in) a spool configured to move axially within the sleeve, wherein the spool is configured to he seated on the seat of the sleeve when the valve is unactuated, and wherein when the valve is actuated, the spool moves such that a gap is formed at the seat; and (iv) a flow restriction disposed downstream of the gap, wherein when the valve is actuated, fluid is allowed to flow from the supply port through the first opening and the gap and through die flow′ restriction prior to flowing through the second opening to the operating port, such that the flow restriction generates an increased pressure level at the gap.

An electro-hydrostatic actuation system and a method for driving a hydraulic actuator, e.g. a hydraulic cylinder, are described, wherein the system comprising a leakage branch, and wherein preferably an additional pump is arranged. The system further comprises a source for providing hydraulic liquid; a high-pressure circuit to direct the hydraulic liquid to a hydraulic actuator, such as e.g. a hydraulic cylinder; a low-pressure circuit having several branches; a main pump for hydraulic liquid arranged in the high-pressure circuit, comprising a housing having a high-pressure section and a low-pressure section, separated by gap sealings, wherein the high-pressure section comprises a first outlet and a second outlet to provide the hydraulic liquid flow in the high-pressure circuit; and wherein the low- pressure section comprises a leakage outlet; an electric motor driving the main pump.

A fluid supply system supplying multiple fluid consumers of a vehicle with fluid, the fluid supply system including: a first pump supplying a first fluid consumer, arranged in a first supply circulation of the vehicle, with fluid; a second pump supplying a second fluid consumer, arranged in a second supply circulation of the vehicle, with fluid; and a directional control valve adjustable between a first valve position and at least one other, second valve position and preferably includes an electromagnetic device for adjusting. The directional control valve allows the fluid to be delivered from the second pump into the first supply circulation in the first valve position and separates the first supply circulation from the second pump, or allows the fluid to be delivered from the second pump into the first supply circulation only to a restricted extent as compared to the first valve position, in the second valve position.

A system and method for detecting the functional state of a piloted or direct-operated isolation valve in a hydraulic circuit is presented. In some examples the hydraulic circuit is a steering circuit and the isolation valve provides selective isolation between a hydraulic actuator and one or more metering valves. In some examples, the isolation valve assembly is movable between a first position, in which fluid flow between the metering valve and the actuator is enabled, and a second position, in which fluid flow between the metering valve and the actuator is blocked. When the isolation valve assembly is moved to one of the first and second positions, an inlet port and a pressure sensing port of the isolation valve assembly are placed in fluid communication with each other. When the isolation valve assembly is moved to the other of the first or second position, a second inlet port and the pressure sensing port are placed in fluid communication.

A robot device of the present disclosure includes at least one artificial muscle that operates by being supplied with liquid; and a liquid supply device that supplies and discharges the liquid to/from the artificial muscle, and the liquid supply device includes a liquid storage part that stores the liquid; a pump that sucks the liquid from the liquid storage part and discharges the liquid; a pressure regulating device that includes a spool and an electromagnetic part that allows the spool to move, and that generates drive pressure for the artificial muscle by regulating source pressure from the pump side, and regulates the source pressure by balancing at least a force given to the spool from the electromagnetic part and a force given to the spool by action of the drive pressure; and a control device that applies a current to the electromagnetic part of the pressure regulating device so that the drive pressure reaches target pressure.

A pneumatically actuated gate assembly, and a kit for making the assembly are provided. The assembly comprising: a gate with an at least one hinge; a battery; a compressed gas cylinder; a first support pivotally supporting the gate with the hinges; a second support; a latch movably mounted on the gate; a keeper for releasable engagement with the latch, the keeper mounted on the second support; a compressed gas system in fluid communication with the compressed gas cylinder; a gate pneumatic system in fluid communication with the compressed gas system, and including a gate pneumatic ram pivotally attached to the first support at a proximal end and attached to the gate at a distal end; a latch pneumatic system in fluid communication with the compressed gas system, and including a latch pneumatic ram attached to the gate and the latch; and a controller, wherein the compressed gas system is configured to provide a controllable pressure of gas to the gate pneumatic system and the latch pneumatic system under control of the controller. A method of using the assembly is also provided.